Watch: Penn Badgley Reacts to Gossip Girl Costar Michelle Trachtenberg's "Surreal" Death (Exclusive)Michelle Trachtenberg's friends are still hurting. One year after the Ice Princess actress tragically died at 39 in February 2025, her former costars Sarah Michelle Gellar and Taylor Momsen shared heartfelt reflections on her memory. "It's weird how the body clock remembers," Taylor, who starred alongside Michelle in Gossip Girl, wrote in a Feb. 26 Instagram post.